Expansion performance and self-stressing behavior of CFST columns considering concrete creep and shrinkage effect  

考虑混凝土徐变和收缩影响的钢管混凝土柱膨胀与自应力性能

作　　者：Xu Li Zeng Hao Pan Jinlong 许荔;曾昊;潘金龙(东南大学土木工程学院,南京210096)

机构地区：[1]School of Civil Engineering,Southeast University,Nanjing 210096,China

出　　处：《Journal of Southeast University(English Edition)》2021年第1期52-58,共7页东南大学学报（英文版）

基　　金：The National Key R&D Program of China(No.2017YFC0703705);the National Natural Science Foundation of China(No.51778183);Jiangsu Planned Projects for Postdoctoral Research Funds(No.2020Z088).

摘　　要：Expansive concrete is used in the steel tube of Concrete-filled steel tubular(CFST)columns to solve the problem of steel-to-concrete debonding.Self-stress is generated between concrete and steel plate due to concrete expansion,which can effectively improve the mechanical performance of CFST columns.Deformation tests were conducted on concrete and CFST columns,respectively.The free deformation of concrete and circumferential deformation of steel tubes were measured and analyzed.A calculation method was proposed to evaluate the hoop strain,self-stress and creep deformation of the CFST columns.The test and calculation results indicate that the proper addition of expansion agent in the internal concrete can keep concrete expansive and generate self-stresses for a long time.The expansion and self-stresses prevent the debonding between the steel tube and the internal concrete.Increasing the dosage of expansive agents and reducing the curing age both increase the expansive deformation and self-stress of CFST columns.Increasing the tube thickness reduces the expansive deformation and increases the initial self-stress of CFST columns.为解决钢管与混凝土的脱黏问题,在钢管混凝土柱中采用了膨胀混凝土.由于混凝土膨胀,钢管与混凝土之间产生自应力,从而有效提升钢管混凝土柱的力学性能.分别对混凝土和钢管混凝土柱进行变形试验,对混凝土的自由变形和钢管的环向变形进行测量和分析,并提出了钢管混凝土柱的环向应变、自应力和徐变的计算方法.试验和计算结果表明:在混凝土内添加合适掺量的膨胀剂可以长期保持混凝土膨胀并产生自应力,从而避免了钢管与内部混凝土间的脱黏;增加膨胀剂用量和减小养护龄期均能提高钢管混凝土柱的膨胀变形和自应力;增加钢管壁厚降低了钢管混凝土柱的膨胀变形,但提高了初始自应力.

关 键 词：concrete-filled steel tubular(CFST) expansive deformation SELF-STRESS CREEP 

分 类 号：TU398.9[建筑科学—结构工程]